iMessages

A report by The Intercept gives information about iMessage conversations. Although Apple secures messages with end-to-end encryption, your contacts may not be as safe. The company automatically logs which phone numbers you contact. Apple can then share this information with law enforcement if ordered to do so.

This isn’t the same as SMS though. When Apple users text each other, the messages use Apple’s proprietary messaging network. These message bubbles appear blue. In contrast, the SMS standard doesn’t use encryption, and these messages appear green in the iMessage app.

Every time you type a phone number in your iPhone to text, the Messages app asks Apple servers whether it should send it as an SMS or iMessage. Apple records every query to figure out which of your contacts use iMessage, and which contacts don’t. The log also contains other metadata:

Date and time when you enter a number

Your IP address

User’s phone number

Image credit: Author

Since Apple appears to keep this information, law enforcement and compel the company to hand the data over. Agencies like the FBI can use devices called pen registers on a suspect’s phone. A pen register or dialed number recorder (DNR) is a device that records all numbers called from a particular phone.

Logs

Logging IP addresses goes against something Apple said in 2013: “We do not store data related to customers’ location.” Apple confirmed that it only keeps these logs for 30 days, after which it deletes them. But a court order can be extended in additional 30-day increments. This means that the police can potentially combine a bunch of 30-day log snapshots together.

The Intercept got its hands on a document about iMessages logs from inside the Florida Department of Law Enforcement‘s Electronic Surveillance Support Team. This agency is notorious for using tools like Stingray, along with regular pen registers. The document is called “iMessage FAQ for Law Enforcement.” It’s designated for “Law Enforcement Sources” and “For Official Use Only.”

It’s pretty common for most phone companies to hand over metadata to law enforcement. After all, the law requires them to do so if ordered. But it’s surprising that Apple can do this too. The company brags that its messaging system is secure.

Image credit: The Intercept

Metadata Is Everything

Apple keeps a log of phone numbers you type into iMessages and potentially in other areas on your iPhone. Even if you never end up talking to these people, it’s possible their numbers still end up in a log. It sounds like the document says that when you open a new chat window and select a contact or phone number to chat with, iMessages sends this info to Apple.

This seems like a limitation of the system itself. Apple has to figure out if the person you’re trying to text is also an Apple user. If it can’t tell the difference, than iMessages becomes useless and, texts use SMS instead.

An Apple spokesperson provided The Intercept with this statement:

“When law enforcement presents us with a valid subpoena or court order, we provide the requested information if it is in our possession. Because iMessage is encrypted end-to-end, we do not have access to the contents of those communications. In some cases, we are able to provide data from server logs that are generated from customers accessing certain apps on their devices. We work closely with law enforcement to help them understand what we can provide and make clear these query logs don’t contain the contents of conversations or prove that any communication actually took place.”

It may not matter if the police can’t read your messages. The metadata is just as important as the message content, if not more so. Former general counsel at the NSA, Stewart Baker has said, “metadata absolutely tells you everything about somebody’s life.”

What You Can Do

Ultimately, it’s up to you to decide whether you want to use iMessages or not. Apple still has a proven track record of standing up for user privacy. Although it’s not clear why Apple retains this information, they still have to follow the law and hand it over, just like everyone else. But there are alternatives.

The most popular secure messaging app is Signal. I’ve talked about Signal plenty of times, both here and here. Like iMessages, Signal provides users with end-to-end encryption. You can send both messages and phone calls. Unlike iMessages, Signal scrambles all of your information. It doesn’t keep logs or other metadata. The developers have recently released a desktop version of Signal.